Download Metformin causes Vitamin B12 Deficiency

Metformin causes Vitamin B12 Deficiency
Sunday, October 31, 2010 by: David Gutierrez, staff writer.
(NaturalNews) Long-term use of the popular diabetes drug metformin (originally marketed as
Glucophage) may cause patients to develop a steadily worsening vitamin B12 deficiency,
Dutch scientists have found.
"Our study shows that this decrease is not a transitory phenomenon, but persists and grows
over time," wrote the Maastricht University Medical Center researchers in the British Medical
Journal.
This is an issue of particular concern given the prevalence of diabetes and the popularity of
metformin as a treatment.
"Metformin is considered a cornerstone in thetreatment of diabetes and is the most
frequently prescribed first line therapy for individuals with type 2 diabetes," the researchers
wrote. "In addition, it is one of a few ... associated with improvements in cardiovascular
morbidity and mortality, which is a major cause of death in patients with type 2 diabetes."
Earlier, short-term studies had found that use of the drug might lead to insufficient levels of
the vitamin in the body. The new study confirmed this trend over the long term.
"Metformin does ... induce vitamin B12 malabsorption, which may increase the risk of
developing vitamin B12 deficiency -- a clinically important and treatable condition," the
researchers wrote.
The researchers assigned 390 Type 2 diabetes patients at the outpatient clinics of three
nonacademic hospitals to take either metformin or a placebo pill three times per day for
more than four years. The average study participant had been diagnosed with diabetes 13
years prior and had been undergoing insulin treatment for seven years. Average participant
age was 61.
Among those taking metformin, vitamin B12 levels began to steadily drop relative to those
who were taking a placebo pill. The biggest drop occurred in the first few months, but the
decrease continued over the course of the study.
After four years, participants in the metformin group had undergone a 19 percent relative
reduction in their levels of the nutrient. They were 11.2 percent more likely than placebo
participants to suffer from B12 insufficiency and 7.2 percent more likely to suffer from
deficiency.
For every 8.9 patients treated with metformin, one would develop insufficient vitamin B12
levels. This increased risk remained after researchers adjusted for other risk factors
including age, duration of diabetes, insulin dose, sex, smoking status and previous treatment
with metformin.
"Our study shows that it is reasonable to assume harm will eventually occur in some patients
with metformin-induced low vitamin B12 levels," the researchers wrote.
The researchers found that metformin seems to inhibit the intestine's absorption of
vitamin B12. Fortunately, calcium supplements appear to reverse this effect.
Vitamin B12 is critical for maintaining nerve and red blood cell health. It can be found in
animal products, nutritional yeast and fortified breakfast cereals. Symptoms of deficiency
include anemia, fatigue, nerve damage and cognitive changes. Because
similar symptoms often occur in diabetics and the elderly, deficiency may be hard to detect
in such populations. Yet while B12 deficiency can carry severe consequences, it is relatively
easy to correct with supplementation.
The researchers suggested that all patients taking metformin have their vitamin B12 levels
tested regularly to avoid potentially severe consequences.
"Vitamin B-12 deficiency is preventable; therefore, our findings suggest that regular
measurement of vitamin B-12 concentrations during long-term metformin treatment should
be strongly considered." the researchers wrote.
Nearly 11 percent of the U.S. population, or 24 million people, suffer from diabetes. Of these
5.7 million are undiagnosed. In addition, 57 million people in the United States alone are
estimated to be pre-diabetic, or at imminent risk of developing the disease.
Worldwide, an estimated 246 million people suffer from the disease. Prevalence is only
expected to increase as the spreading Western diet and lifestyle lead to increasing rates of
obesity.
Sources for this story
include: http://www.reuters.com/article/idUS...http://www.medscape.com/viewarticle... http://
www.medpagetoday.com/Endocri....